- Add allow_multiple_instances field to Crontab model (default: 0 for single instance)
- Add validation for new field in commonCronSchema
- Add getAllPids and killAllTasks utility functions
- Update stop method to kill ALL running instances of a task
- Update runCron to respect allow_multiple_instances config
- Backward compatible: defaults to single instance mode
Co-authored-by: whyour <22700758+whyour@users.noreply.github.com>